Technical Field
The inventions relate to apparatus and methods for optical fiber communications.
Related Art
This section introduces aspects that may be helpful to facilitating a better understanding of the inventions. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.
The technique of optical spatial division multiplexing involves transmitted data over an optical fiber line with a plurality of optical spatial propagating modes. In optical spatial division multiplexing, at least, two of the optical spatial propagating modes have different phase and/or intensity profiles lateral to the propagation direction and may carry different data.
Presently, interest has been generated in optical spatial division multiplexing systems for optical transport networks. Optical transport networks usually operate in optical communication bands between about 1.5 micrometers and about 1.7 micrometers or near 1.3 micrometer. In these wavelength bands, conventional glass optical fibers have low attenuation or loss. Such optical transport networks often use edge emitting laser chips, which provide narrow band light emission. Such optical transport networks often use costly optical components and costly data processing components, e.g., to compensate for chromatic dispersion, inter-channel and/or intra-channel interference, noise, nonlinear optical distortions, and/or optical loss.